England head coach Eddie Jones is concerned for the welfare of Johnny Sexton ahead of Saturday's Twickenham showdown and believes the parents of Ireland's fly-half will share his anxiety.

Jones has heightened tensions between the rival camps by expressing his alarm at the 'whiplash injury' sustained by Sexton during the 10-9 defeat by France in the previous round of the RBS 6 Nations.

Joe Schmidt, Ireland's coach, has downplayed any concussion fears after the playmaker was stood down for 12 weeks in late 2014 having sustained four head injuries inside a year and he has taken several further blows since.

Schmidt described Sexton's latest setback as "neck and shoulder, more of a whiplash injury" and the British and Irish Lion has been cleared to play at Twickenham where the champions will attempt to rescue their Six Nations.

Jones is uneasy, however, and questions the health of the player given he has suffered what he terms as "severe trauma".

"Sexton is an interesting one, they've talked about him having a whiplash injury which is not a great thing to talk about,'' Jones said.

"I'm sure his mother and father would be worried about that. Hopefully, the lad's all right to play on Saturday.

"I'd just be worried about his welfare if he's had whiplash injuries. That's quite a distinct way to talk about the injury. You don't like to see that with any player.

"If you're saying a guy has got whiplash then he's had a severe trauma. Maybe they used the wrong term, but if you've had severe trauma then you've got to worry about the welfare of the player."

When it was put to Jones that Sexton has passed the head injury assessment, the Australian replied: "The only thing I've suggested is that if they say he's had whiplash injuries, then I'd be worried about him. That's all I'm suggesting.

"We've got medical staff here, the best medical staff in England, and we'll make the best decision for the player. I'm sure Ireland have done the same."

Schmidt took a diplomatic line when responding to Jones, who views mind games as a key element of a coach's role.

"People are within their rights to make whatever observation they like from outside the environment. But we know how things are inside the environment," Schmidt said.

Jones bristled when asked if targeting the opposition fly-half - who is often the weak link in a side's defensive chain - is a legitimate tactic.

It is a method that France have employed against Sexton in recent matches and repeated in Paris on February 13, with Yoann Maestri receiving a citing commissioner's warning for a late hit on the 30-year-old.

Sexton appeared dazed on leaving the field at the Stade de France after several questionable hits.

"We target players all the time. That's part of rugby, is it not? Is there some sort of special law there?" Jones said.

"Rugby's a game of XV players on the field. When we're attacking, we're attacking weak defenders. Why would we run at the strongest defender?

"I'm not saying Sexton is a weak defender. Maybe France did. We're going to be targeting players in the Ireland side.

"We want to win and you win a game of rugby by attacking their weak points and to say that's unfair is just ridiculous.

"Remember David Knox, who played for the Brumbies and New South Wales? He couldn't tackle to save his life and teams used to send runners at him all the time.

"I remember Inga Tuigamala. New South Wales played Auckland when Graham Henry was coaching Auckland.

"I remember sitting on the bench and Tuigamala kept on running at David Knox and absolutely terrorised him. That's been happening since Adam and Eve were around. To ask 'is that a legitimate tactic?' is absolutely ridiculous.

"You think Ireland are not going to send Robbie Henshaw at George Ford at the weekend? Give me a break.

"But it's not the size of the dog in the fight, it's the size of the fight in the dog. I've got no worries about George Ford standing up to Henshaw.

"Sexton is not a weak defender. He's a big boy. He's twice the size of George Ford. I'm sure he can look after himself. He's hardly a shrinking violet."

Jones, who has launched his England reign with away wins over Scotland and Italy, is happy to target players who are carrying injury.

"You always do. I remember at the 2003 World Cup, Jonny Wilkinson was supposed to have a bad right shoulder," the former Australia coach said.

"We kept on running at him, he kept on picking people up and putting them on their head, so his shoulder wasn't too bad!"

Ford, who will line-up opposite Sexton at Twickenham, insists fly-halves are targeted more than ever in the modern game and will be on the receiving end of a cheap shot around once each match.

"You might get one a game on average. They are things that come with the game these days," Ford said.